Hines' Twitter account was deleted the day of Mary's suicide, but the New York Post reported the actress wrote about spending time with the Kennedys son, Aiden, and how she accompanied Robert to a birthday celebration for Glenn Close, who was also good friends with Mary Kennedy, 52.
The Post reported Robert's sister, Kerry Kennedy, who introduced him to Mary, tweeted a picture of Glenn Close, Bobby and Cheryl Hines on Twitter.
I got to tell #GlenClose what an inspiration she has always been to me, Hines tweeted April 15.
It appears that Hines, 46, replacing Mary in Robert's life was too much for Mary Kennedy, who battled struggles with depression and alcohol abuse, to bear.
Mary Kennedy hanged herself in her home last week in Bedford, N.Y. However, Mary did not leave a suicide note indicating why she chose to end her life.
She faced losing her kids, and his relationship with Cheryl Hines was humiliating, a source close to Mary Kennedy told the Post. At an event last month, he walked the red carpet with Cheryl as a couple and took the kids.
The Post described Mary as being isolated in her Bedford mansion, drowning in sorrow, alcohol and death.
Hines tweeted about how close she was getting to Aiden Kennedy, the young son of Bobby and Mary.
Rabid, unhinged New England zealotry by 10-yr.-old Aidan Kennedy has nearly turned me into Pats fan, she wrote Feb. 5, according to the Post.
Mary Kennedy also faced the humiliating situation of having Hines accompany Robert, 58, and his kids to public events, the Daily Mail reported.
Hines also gushed about the food at Armonk's Burgers & Shakes, a popular hamburger joint that Mary and Robert Kennedy used to take their kids.
Robert and Mary Kennedy had been separated since 2010, and friction between the couple spilled over after Mary's suicide, as her family blocked Robert from attending a private memorial service. Instead, Robert took his four children to Florida instead of the memorial.